An Easy One

Welcome to riddle Saturday. I know, you’re chomping at the bit and ready to go, right?
So…
This is a regular image clue, but I also got a kick out of the snide remark.
Today’s riddle answer is from the real world.
It’s a set of four…
… but it’s not really a set.
Yeah, it’s an orange.
It’s very close to home, all things considered.
This set of four (that’s not really a set) was discovered together.
Each of the four is dramatically different in appearance.
One of the four probably smells like a rotten egg.
Another one probably reminds you of Antarctica.
And one has a leading edge that is darker than its trailing one.
There you go! Not many clues today, but you don’t really need that many. Not really. No, you don’t.